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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
e9be9d5e MS |
2 | /* |
3 | * | |
4 | * Copyright (C) 2011 Novell Inc. | |
e9be9d5e MS |
5 | */ |
6 | ||
5b825c3a | 7 | #include <uapi/linux/magic.h> |
e9be9d5e MS |
8 | #include <linux/fs.h> |
9 | #include <linux/namei.h> | |
10 | #include <linux/xattr.h> | |
e9be9d5e | 11 | #include <linux/mount.h> |
e9be9d5e MS |
12 | #include <linux/parser.h> |
13 | #include <linux/module.h> | |
cc259639 | 14 | #include <linux/statfs.h> |
f45827e8 | 15 | #include <linux/seq_file.h> |
d837a49b | 16 | #include <linux/posix_acl_xattr.h> |
e487d889 | 17 | #include <linux/exportfs.h> |
2b1a7746 | 18 | #include <linux/file.h> |
1784fbc2 | 19 | #include <linux/fs_context.h> |
dcb399de | 20 | #include <linux/fs_parser.h> |
e9be9d5e | 21 | #include "overlayfs.h" |
7fb7998b | 22 | #include "params.h" |
e9be9d5e MS |
23 | |
24 | MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); | |
25 | MODULE_DESCRIPTION("Overlay filesystem"); | |
26 | MODULE_LICENSE("GPL"); | |
27 | ||
e9be9d5e MS |
28 | |
29 | struct ovl_dir_cache; | |
30 | ||
11b3f8ae | 31 | static struct dentry *ovl_d_real(struct dentry *dentry, enum d_real_type type) |
d101a125 | 32 | { |
11b3f8ae | 33 | struct dentry *upper, *lower; |
184996e9 | 34 | int err; |
d101a125 | 35 | |
11b3f8ae AG |
36 | switch (type) { |
37 | case D_REAL_DATA: | |
38 | case D_REAL_METADATA: | |
39 | break; | |
40 | default: | |
def3ae83 | 41 | goto bug; |
11b3f8ae | 42 | } |
e8c985ba | 43 | |
ca4c8a3a | 44 | if (!d_is_reg(dentry)) { |
def3ae83 AG |
45 | /* d_real_inode() is only relevant for regular files */ |
46 | return dentry; | |
d101a125 MS |
47 | } |
48 | ||
11b3f8ae AG |
49 | upper = ovl_dentry_upper(dentry); |
50 | if (upper && (type == D_REAL_METADATA || | |
51 | ovl_has_upperdata(d_inode(dentry)))) | |
52 | return upper; | |
d101a125 | 53 | |
11b3f8ae AG |
54 | if (type == D_REAL_METADATA) { |
55 | lower = ovl_dentry_lower(dentry); | |
56 | goto real_lower; | |
57 | } | |
2c3d7358 | 58 | |
41665644 | 59 | /* |
11b3f8ae | 60 | * Best effort lazy lookup of lowerdata for D_REAL_DATA case to return |
41665644 | 61 | * the real lowerdata dentry. The only current caller of d_real() with |
11b3f8ae | 62 | * D_REAL_DATA is d_real_inode() from trace_uprobe and this caller is |
41665644 AG |
63 | * likely going to be followed reading from the file, before placing |
64 | * uprobes on offset within the file, so lowerdata should be available | |
65 | * when setting the uprobe. | |
66 | */ | |
184996e9 AL |
67 | err = ovl_verify_lowerdata(dentry); |
68 | if (err) | |
69 | goto bug; | |
cef4cbff MS |
70 | lower = ovl_dentry_lowerdata(dentry); |
71 | if (!lower) | |
d101a125 MS |
72 | goto bug; |
73 | ||
11b3f8ae AG |
74 | real_lower: |
75 | /* Handle recursion into stacked lower fs */ | |
76 | return d_real(lower, type); | |
c4fcfc16 | 77 | |
d101a125 | 78 | bug: |
11b3f8ae | 79 | WARN(1, "%s(%pd4, %d): real dentry not found\n", __func__, dentry, type); |
d101a125 MS |
80 | return dentry; |
81 | } | |
82 | ||
3bb7df92 | 83 | static int ovl_revalidate_real(struct dentry *d, unsigned int flags, bool weak) |
7c03b5d4 | 84 | { |
7c03b5d4 MS |
85 | int ret = 1; |
86 | ||
41665644 AG |
87 | if (!d) |
88 | return 1; | |
89 | ||
3bb7df92 MS |
90 | if (weak) { |
91 | if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) | |
92 | ret = d->d_op->d_weak_revalidate(d, flags); | |
93 | } else if (d->d_flags & DCACHE_OP_REVALIDATE) { | |
94 | ret = d->d_op->d_revalidate(d, flags); | |
95 | if (!ret) { | |
96 | if (!(flags & LOOKUP_RCU)) | |
97 | d_invalidate(d); | |
98 | ret = -ESTALE; | |
7c03b5d4 MS |
99 | } |
100 | } | |
3bb7df92 | 101 | return ret; |
7c03b5d4 MS |
102 | } |
103 | ||
3bb7df92 MS |
104 | static int ovl_dentry_revalidate_common(struct dentry *dentry, |
105 | unsigned int flags, bool weak) | |
7c03b5d4 | 106 | { |
c54719c9 AV |
107 | struct ovl_entry *oe; |
108 | struct ovl_path *lowerstack; | |
672e4268 | 109 | struct inode *inode = d_inode_rcu(dentry); |
bccece1e | 110 | struct dentry *upper; |
7c03b5d4 MS |
111 | unsigned int i; |
112 | int ret = 1; | |
113 | ||
672e4268 CZ |
114 | /* Careful in RCU mode */ |
115 | if (!inode) | |
116 | return -ECHILD; | |
117 | ||
c54719c9 AV |
118 | oe = OVL_I_E(inode); |
119 | lowerstack = ovl_lowerstack(oe); | |
672e4268 | 120 | upper = ovl_i_dentry_upper(inode); |
bccece1e MS |
121 | if (upper) |
122 | ret = ovl_revalidate_real(upper, flags, weak); | |
123 | ||
5522c9c7 AG |
124 | for (i = 0; ret > 0 && i < ovl_numlower(oe); i++) |
125 | ret = ovl_revalidate_real(lowerstack[i].dentry, flags, weak); | |
126 | ||
7c03b5d4 MS |
127 | return ret; |
128 | } | |
129 | ||
3bb7df92 MS |
130 | static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) |
131 | { | |
132 | return ovl_dentry_revalidate_common(dentry, flags, false); | |
133 | } | |
134 | ||
135 | static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) | |
136 | { | |
137 | return ovl_dentry_revalidate_common(dentry, flags, true); | |
138 | } | |
139 | ||
e9be9d5e | 140 | static const struct dentry_operations ovl_dentry_operations = { |
d101a125 | 141 | .d_real = ovl_d_real, |
7c03b5d4 MS |
142 | .d_revalidate = ovl_dentry_revalidate, |
143 | .d_weak_revalidate = ovl_dentry_weak_revalidate, | |
144 | }; | |
145 | ||
13cf199d AG |
146 | static struct kmem_cache *ovl_inode_cachep; |
147 | ||
148 | static struct inode *ovl_alloc_inode(struct super_block *sb) | |
149 | { | |
fd60b288 | 150 | struct ovl_inode *oi = alloc_inode_sb(sb, ovl_inode_cachep, GFP_KERNEL); |
13cf199d | 151 | |
b3885bd6 HN |
152 | if (!oi) |
153 | return NULL; | |
154 | ||
04a01ac7 | 155 | oi->cache = NULL; |
cf31c463 | 156 | oi->redirect = NULL; |
04a01ac7 | 157 | oi->version = 0; |
13c72075 | 158 | oi->flags = 0; |
09d8b586 | 159 | oi->__upperdentry = NULL; |
2b21da92 | 160 | oi->lowerdata_redirect = NULL; |
0af950f5 | 161 | oi->oe = NULL; |
a015dafc | 162 | mutex_init(&oi->lock); |
25b7713a | 163 | |
13cf199d AG |
164 | return &oi->vfs_inode; |
165 | } | |
166 | ||
0b269ded | 167 | static void ovl_free_inode(struct inode *inode) |
13cf199d | 168 | { |
0b269ded | 169 | struct ovl_inode *oi = OVL_I(inode); |
13cf199d | 170 | |
0b269ded | 171 | kfree(oi->redirect); |
d9e8319a | 172 | kfree(oi->oe); |
0b269ded AV |
173 | mutex_destroy(&oi->lock); |
174 | kmem_cache_free(ovl_inode_cachep, oi); | |
13cf199d AG |
175 | } |
176 | ||
177 | static void ovl_destroy_inode(struct inode *inode) | |
178 | { | |
09d8b586 MS |
179 | struct ovl_inode *oi = OVL_I(inode); |
180 | ||
181 | dput(oi->__upperdentry); | |
d9e8319a | 182 | ovl_stack_put(ovl_lowerstack(oi->oe), ovl_numlower(oi->oe)); |
2664bd08 VG |
183 | if (S_ISDIR(inode->i_mode)) |
184 | ovl_dir_cache_free(inode); | |
2b21da92 AG |
185 | else |
186 | kfree(oi->lowerdata_redirect); | |
13cf199d AG |
187 | } |
188 | ||
a9075cdb MS |
189 | static void ovl_put_super(struct super_block *sb) |
190 | { | |
f01d0889 | 191 | struct ovl_fs *ofs = OVL_FS(sb); |
a9075cdb | 192 | |
1784fbc2 CB |
193 | if (ofs) |
194 | ovl_free_fs(ofs); | |
a9075cdb MS |
195 | } |
196 | ||
e8d4bfe3 | 197 | /* Sync real dirty inodes in upper filesystem (if it exists) */ |
e593b2bf AG |
198 | static int ovl_sync_fs(struct super_block *sb, int wait) |
199 | { | |
f01d0889 | 200 | struct ovl_fs *ofs = OVL_FS(sb); |
e593b2bf AG |
201 | struct super_block *upper_sb; |
202 | int ret; | |
203 | ||
335d3fc5 SD |
204 | ret = ovl_sync_status(ofs); |
205 | /* | |
206 | * We have to always set the err, because the return value isn't | |
207 | * checked in syncfs, and instead indirectly return an error via | |
208 | * the sb's writeback errseq, which VFS inspects after this call. | |
209 | */ | |
210 | if (ret < 0) { | |
211 | errseq_set(&sb->s_wb_err, -EIO); | |
212 | return -EIO; | |
213 | } | |
214 | ||
215 | if (!ret) | |
216 | return ret; | |
e8d4bfe3 CX |
217 | |
218 | /* | |
32b1924b KK |
219 | * Not called for sync(2) call or an emergency sync (SB_I_SKIP_SYNC). |
220 | * All the super blocks will be iterated, including upper_sb. | |
e8d4bfe3 CX |
221 | * |
222 | * If this is a syncfs(2) call, then we do need to call | |
223 | * sync_filesystem() on upper_sb, but enough if we do it when being | |
224 | * called with wait == 1. | |
225 | */ | |
226 | if (!wait) | |
e593b2bf AG |
227 | return 0; |
228 | ||
08f4c7c8 | 229 | upper_sb = ovl_upper_mnt(ofs)->mnt_sb; |
e8d4bfe3 | 230 | |
e593b2bf | 231 | down_read(&upper_sb->s_umount); |
e8d4bfe3 | 232 | ret = sync_filesystem(upper_sb); |
e593b2bf | 233 | up_read(&upper_sb->s_umount); |
e8d4bfe3 | 234 | |
e593b2bf AG |
235 | return ret; |
236 | } | |
237 | ||
cc259639 AW |
238 | /** |
239 | * ovl_statfs | |
9c5dd803 | 240 | * @dentry: The dentry to query |
cc259639 AW |
241 | * @buf: The struct kstatfs to fill in with stats |
242 | * | |
243 | * Get the filesystem statistics. As writes always target the upper layer | |
4ebc5818 | 244 | * filesystem pass the statfs to the upper filesystem (if it exists) |
cc259639 AW |
245 | */ |
246 | static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) | |
247 | { | |
b0504bfe AG |
248 | struct super_block *sb = dentry->d_sb; |
249 | struct ovl_fs *ofs = OVL_FS(sb); | |
250 | struct dentry *root_dentry = sb->s_root; | |
cc259639 AW |
251 | struct path path; |
252 | int err; | |
253 | ||
4ebc5818 | 254 | ovl_path_real(root_dentry, &path); |
cc259639 AW |
255 | |
256 | err = vfs_statfs(&path, buf); | |
257 | if (!err) { | |
6b2d5fe4 | 258 | buf->f_namelen = ofs->namelen; |
cc259639 | 259 | buf->f_type = OVERLAYFS_SUPER_MAGIC; |
b0504bfe AG |
260 | if (ovl_has_fsid(ofs)) |
261 | buf->f_fsid = uuid_to_fsid(sb->s_uuid.b); | |
cc259639 AW |
262 | } |
263 | ||
264 | return err; | |
265 | } | |
266 | ||
e9be9d5e | 267 | static const struct super_operations ovl_super_operations = { |
13cf199d | 268 | .alloc_inode = ovl_alloc_inode, |
0b269ded | 269 | .free_inode = ovl_free_inode, |
13cf199d AG |
270 | .destroy_inode = ovl_destroy_inode, |
271 | .drop_inode = generic_delete_inode, | |
e9be9d5e | 272 | .put_super = ovl_put_super, |
e593b2bf | 273 | .sync_fs = ovl_sync_fs, |
cc259639 | 274 | .statfs = ovl_statfs, |
f45827e8 | 275 | .show_options = ovl_show_options, |
e9be9d5e MS |
276 | }; |
277 | ||
e9be9d5e | 278 | #define OVL_WORKDIR_NAME "work" |
02bcd157 | 279 | #define OVL_INDEXDIR_NAME "index" |
e9be9d5e | 280 | |
ad204488 | 281 | static struct dentry *ovl_workdir_create(struct ovl_fs *ofs, |
6b8aa129 | 282 | const char *name, bool persist) |
e9be9d5e | 283 | { |
ad204488 | 284 | struct inode *dir = ofs->workbasedir->d_inode; |
08f4c7c8 | 285 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
e9be9d5e MS |
286 | struct dentry *work; |
287 | int err; | |
288 | bool retried = false; | |
289 | ||
5955102c | 290 | inode_lock_nested(dir, I_MUTEX_PARENT); |
e9be9d5e | 291 | retry: |
22f289ce | 292 | work = ovl_lookup_upper(ofs, name, ofs->workbasedir, strlen(name)); |
e9be9d5e MS |
293 | |
294 | if (!IS_ERR(work)) { | |
c11b9fdd MS |
295 | struct iattr attr = { |
296 | .ia_valid = ATTR_MODE, | |
32a3d848 | 297 | .ia_mode = S_IFDIR | 0, |
c11b9fdd | 298 | }; |
e9be9d5e MS |
299 | |
300 | if (work->d_inode) { | |
301 | err = -EEXIST; | |
302 | if (retried) | |
303 | goto out_dput; | |
304 | ||
6b8aa129 AG |
305 | if (persist) |
306 | goto out_unlock; | |
307 | ||
e9be9d5e | 308 | retried = true; |
576bb263 | 309 | err = ovl_workdir_cleanup(ofs, dir, mnt, work, 0); |
e9be9d5e | 310 | dput(work); |
235ce9ed AG |
311 | if (err == -EINVAL) { |
312 | work = ERR_PTR(err); | |
313 | goto out_unlock; | |
314 | } | |
e9be9d5e MS |
315 | goto retry; |
316 | } | |
317 | ||
576bb263 | 318 | err = ovl_mkdir_real(ofs, dir, &work, attr.ia_mode); |
1f5573cf MS |
319 | if (err) |
320 | goto out_dput; | |
321 | ||
322 | /* Weird filesystem returning with hashed negative (kernfs)? */ | |
323 | err = -EINVAL; | |
324 | if (d_really_is_negative(work)) | |
325 | goto out_dput; | |
c11b9fdd | 326 | |
cb348edb MS |
327 | /* |
328 | * Try to remove POSIX ACL xattrs from workdir. We are good if: | |
329 | * | |
330 | * a) success (there was a POSIX ACL xattr and was removed) | |
331 | * b) -ENODATA (there was no POSIX ACL xattr) | |
332 | * c) -EOPNOTSUPP (POSIX ACL xattrs are not supported) | |
333 | * | |
334 | * There are various other error values that could effectively | |
335 | * mean that the xattr doesn't exist (e.g. -ERANGE is returned | |
336 | * if the xattr name is too long), but the set of filesystems | |
337 | * allowed as upper are limited to "normal" ones, where checking | |
338 | * for the above two errors is sufficient. | |
339 | */ | |
31acceb9 | 340 | err = ovl_do_remove_acl(ofs, work, XATTR_NAME_POSIX_ACL_DEFAULT); |
e1ff3dd1 | 341 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
342 | goto out_dput; |
343 | ||
31acceb9 | 344 | err = ovl_do_remove_acl(ofs, work, XATTR_NAME_POSIX_ACL_ACCESS); |
e1ff3dd1 | 345 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
346 | goto out_dput; |
347 | ||
348 | /* Clear any inherited mode bits */ | |
349 | inode_lock(work->d_inode); | |
a15506ea | 350 | err = ovl_do_notify_change(ofs, work, &attr); |
c11b9fdd MS |
351 | inode_unlock(work->d_inode); |
352 | if (err) | |
353 | goto out_dput; | |
6b8aa129 AG |
354 | } else { |
355 | err = PTR_ERR(work); | |
356 | goto out_err; | |
e9be9d5e MS |
357 | } |
358 | out_unlock: | |
2068cf7d | 359 | inode_unlock(dir); |
e9be9d5e MS |
360 | return work; |
361 | ||
362 | out_dput: | |
363 | dput(work); | |
6b8aa129 | 364 | out_err: |
1bd0a3ae | 365 | pr_warn("failed to create directory %s/%s (errno: %i); mounting read-only\n", |
ad204488 | 366 | ofs->config.workdir, name, -err); |
6b8aa129 | 367 | work = NULL; |
e9be9d5e MS |
368 | goto out_unlock; |
369 | } | |
370 | ||
2d343087 | 371 | static int ovl_check_namelen(const struct path *path, struct ovl_fs *ofs, |
6b2d5fe4 | 372 | const char *name) |
ab508822 | 373 | { |
ab508822 | 374 | struct kstatfs statfs; |
6b2d5fe4 MS |
375 | int err = vfs_statfs(path, &statfs); |
376 | ||
377 | if (err) | |
1bd0a3ae | 378 | pr_err("statfs failed on '%s'\n", name); |
6b2d5fe4 MS |
379 | else |
380 | ofs->namelen = max(ofs->namelen, statfs.f_namelen); | |
381 | ||
382 | return err; | |
383 | } | |
384 | ||
385 | static int ovl_lower_dir(const char *name, struct path *path, | |
f4288844 | 386 | struct ovl_fs *ofs, int *stack_depth) |
6b2d5fe4 | 387 | { |
e487d889 | 388 | int fh_type; |
6b2d5fe4 | 389 | int err; |
ab508822 | 390 | |
6b2d5fe4 MS |
391 | err = ovl_check_namelen(path, ofs, name); |
392 | if (err) | |
b8e42a65 | 393 | return err; |
6b2d5fe4 | 394 | |
ab508822 MS |
395 | *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); |
396 | ||
02bcd157 | 397 | /* |
f168f109 AG |
398 | * The inodes index feature and NFS export need to encode and decode |
399 | * file handles, so they require that all layers support them. | |
02bcd157 | 400 | */ |
e487d889 | 401 | fh_type = ovl_can_decode_fh(path->dentry->d_sb); |
f168f109 | 402 | if ((ofs->config.nfs_export || |
e487d889 | 403 | (ofs->config.index && ofs->config.upperdir)) && !fh_type) { |
02bcd157 | 404 | ofs->config.index = false; |
f168f109 | 405 | ofs->config.nfs_export = false; |
1bd0a3ae | 406 | pr_warn("fs on '%s' does not support file handles, falling back to index=off,nfs_export=off.\n", |
f168f109 | 407 | name); |
02bcd157 | 408 | } |
16aac5ad | 409 | ofs->nofh |= !fh_type; |
b0e0f697 AG |
410 | /* |
411 | * Decoding origin file handle is required for persistent st_ino. | |
412 | * Without persistent st_ino, xino=auto falls back to xino=off. | |
413 | */ | |
414 | if (ofs->config.xino == OVL_XINO_AUTO && | |
415 | ofs->config.upperdir && !fh_type) { | |
416 | ofs->config.xino = OVL_XINO_OFF; | |
417 | pr_warn("fs on '%s' does not support file handles, falling back to xino=off.\n", | |
418 | name); | |
419 | } | |
02bcd157 | 420 | |
e487d889 AG |
421 | /* Check if lower fs has 32bit inode numbers */ |
422 | if (fh_type != FILEID_INO32_GEN) | |
0f831ec8 | 423 | ofs->xino_mode = -1; |
e487d889 | 424 | |
ab508822 | 425 | return 0; |
ab508822 MS |
426 | } |
427 | ||
e9be9d5e MS |
428 | /* Workdir should not be subdir of upperdir and vice versa */ |
429 | static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) | |
430 | { | |
431 | bool ok = false; | |
432 | ||
433 | if (workdir != upperdir) { | |
a8b00268 AV |
434 | struct dentry *trap = lock_rename(workdir, upperdir); |
435 | if (!IS_ERR(trap)) | |
436 | unlock_rename(workdir, upperdir); | |
437 | ok = (trap == NULL); | |
e9be9d5e MS |
438 | } |
439 | return ok; | |
440 | } | |
441 | ||
146d62e5 AG |
442 | static int ovl_setup_trap(struct super_block *sb, struct dentry *dir, |
443 | struct inode **ptrap, const char *name) | |
444 | { | |
445 | struct inode *trap; | |
446 | int err; | |
447 | ||
448 | trap = ovl_get_trap_inode(sb, dir); | |
1dac6f5b AB |
449 | err = PTR_ERR_OR_ZERO(trap); |
450 | if (err) { | |
146d62e5 | 451 | if (err == -ELOOP) |
1bd0a3ae | 452 | pr_err("conflicting %s path\n", name); |
146d62e5 AG |
453 | return err; |
454 | } | |
455 | ||
456 | *ptrap = trap; | |
457 | return 0; | |
458 | } | |
459 | ||
0be0bfd2 AG |
460 | /* |
461 | * Determine how we treat concurrent use of upperdir/workdir based on the | |
462 | * index feature. This is papering over mount leaks of container runtimes, | |
463 | * for example, an old overlay mount is leaked and now its upperdir is | |
464 | * attempted to be used as a lower layer in a new overlay mount. | |
465 | */ | |
466 | static int ovl_report_in_use(struct ovl_fs *ofs, const char *name) | |
467 | { | |
468 | if (ofs->config.index) { | |
1bd0a3ae | 469 | pr_err("%s is in-use as upperdir/workdir of another mount, mount with '-o index=off' to override exclusive upperdir protection.\n", |
0be0bfd2 AG |
470 | name); |
471 | return -EBUSY; | |
472 | } else { | |
1bd0a3ae | 473 | pr_warn("%s is in-use as upperdir/workdir of another mount, accessing files from both mounts will result in undefined behavior.\n", |
0be0bfd2 AG |
474 | name); |
475 | return 0; | |
476 | } | |
477 | } | |
478 | ||
146d62e5 | 479 | static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, |
b36a5780 CB |
480 | struct ovl_layer *upper_layer, |
481 | const struct path *upperpath) | |
6ee8acf0 | 482 | { |
5064975e | 483 | struct vfsmount *upper_mnt; |
6ee8acf0 MS |
484 | int err; |
485 | ||
e21a6c57 AG |
486 | /* Upperdir path should not be r/o */ |
487 | if (__mnt_is_readonly(upperpath->mnt)) { | |
1bd0a3ae | 488 | pr_err("upper fs is r/o, try multi-lower layers mount\n"); |
6ee8acf0 MS |
489 | err = -EINVAL; |
490 | goto out; | |
491 | } | |
492 | ||
ad204488 | 493 | err = ovl_check_namelen(upperpath, ofs, ofs->config.upperdir); |
6ee8acf0 MS |
494 | if (err) |
495 | goto out; | |
496 | ||
b8e42a65 | 497 | err = ovl_setup_trap(sb, upperpath->dentry, &upper_layer->trap, |
146d62e5 AG |
498 | "upperdir"); |
499 | if (err) | |
500 | goto out; | |
501 | ||
5064975e MS |
502 | upper_mnt = clone_private_mount(upperpath); |
503 | err = PTR_ERR(upper_mnt); | |
504 | if (IS_ERR(upper_mnt)) { | |
1bd0a3ae | 505 | pr_err("failed to clone upperpath\n"); |
5064975e MS |
506 | goto out; |
507 | } | |
508 | ||
509 | /* Don't inherit atime flags */ | |
510 | upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME); | |
b8e42a65 MS |
511 | upper_layer->mnt = upper_mnt; |
512 | upper_layer->idx = 0; | |
513 | upper_layer->fsid = 0; | |
8c25741a | 514 | |
654255fa JX |
515 | /* |
516 | * Inherit SB_NOSEC flag from upperdir. | |
517 | * | |
518 | * This optimization changes behavior when a security related attribute | |
519 | * (suid/sgid/security.*) is changed on an underlying layer. This is | |
520 | * okay because we don't yet have guarantees in that case, but it will | |
521 | * need careful treatment once we want to honour changes to underlying | |
522 | * filesystems. | |
523 | */ | |
524 | if (upper_mnt->mnt_sb->s_flags & SB_NOSEC) | |
525 | sb->s_flags |= SB_NOSEC; | |
526 | ||
08f4c7c8 | 527 | if (ovl_inuse_trylock(ovl_upper_mnt(ofs)->mnt_root)) { |
8c25741a | 528 | ofs->upperdir_locked = true; |
8c25741a | 529 | } else { |
0be0bfd2 AG |
530 | err = ovl_report_in_use(ofs, "upperdir"); |
531 | if (err) | |
532 | goto out; | |
8c25741a MS |
533 | } |
534 | ||
6ee8acf0 MS |
535 | err = 0; |
536 | out: | |
537 | return err; | |
538 | } | |
539 | ||
cad218ab AG |
540 | /* |
541 | * Returns 1 if RENAME_WHITEOUT is supported, 0 if not supported and | |
542 | * negative values if error is encountered. | |
543 | */ | |
576bb263 | 544 | static int ovl_check_rename_whiteout(struct ovl_fs *ofs) |
cad218ab | 545 | { |
576bb263 | 546 | struct dentry *workdir = ofs->workdir; |
cad218ab AG |
547 | struct inode *dir = d_inode(workdir); |
548 | struct dentry *temp; | |
549 | struct dentry *dest; | |
550 | struct dentry *whiteout; | |
551 | struct name_snapshot name; | |
552 | int err; | |
553 | ||
554 | inode_lock_nested(dir, I_MUTEX_PARENT); | |
555 | ||
576bb263 | 556 | temp = ovl_create_temp(ofs, workdir, OVL_CATTR(S_IFREG | 0)); |
cad218ab AG |
557 | err = PTR_ERR(temp); |
558 | if (IS_ERR(temp)) | |
559 | goto out_unlock; | |
560 | ||
576bb263 | 561 | dest = ovl_lookup_temp(ofs, workdir); |
cad218ab AG |
562 | err = PTR_ERR(dest); |
563 | if (IS_ERR(dest)) { | |
564 | dput(temp); | |
565 | goto out_unlock; | |
566 | } | |
567 | ||
568 | /* Name is inline and stable - using snapshot as a copy helper */ | |
569 | take_dentry_name_snapshot(&name, temp); | |
576bb263 | 570 | err = ovl_do_rename(ofs, dir, temp, dir, dest, RENAME_WHITEOUT); |
cad218ab AG |
571 | if (err) { |
572 | if (err == -EINVAL) | |
573 | err = 0; | |
574 | goto cleanup_temp; | |
575 | } | |
576 | ||
22f289ce | 577 | whiteout = ovl_lookup_upper(ofs, name.name.name, workdir, name.name.len); |
cad218ab AG |
578 | err = PTR_ERR(whiteout); |
579 | if (IS_ERR(whiteout)) | |
580 | goto cleanup_temp; | |
581 | ||
bc8df7a3 | 582 | err = ovl_upper_is_whiteout(ofs, whiteout); |
cad218ab AG |
583 | |
584 | /* Best effort cleanup of whiteout and temp file */ | |
585 | if (err) | |
576bb263 | 586 | ovl_cleanup(ofs, dir, whiteout); |
cad218ab AG |
587 | dput(whiteout); |
588 | ||
589 | cleanup_temp: | |
576bb263 | 590 | ovl_cleanup(ofs, dir, temp); |
cad218ab AG |
591 | release_dentry_name_snapshot(&name); |
592 | dput(temp); | |
593 | dput(dest); | |
594 | ||
595 | out_unlock: | |
596 | inode_unlock(dir); | |
597 | ||
598 | return err; | |
599 | } | |
600 | ||
576bb263 CB |
601 | static struct dentry *ovl_lookup_or_create(struct ovl_fs *ofs, |
602 | struct dentry *parent, | |
c86243b0 VG |
603 | const char *name, umode_t mode) |
604 | { | |
605 | size_t len = strlen(name); | |
606 | struct dentry *child; | |
607 | ||
608 | inode_lock_nested(parent->d_inode, I_MUTEX_PARENT); | |
22f289ce | 609 | child = ovl_lookup_upper(ofs, name, parent, len); |
c86243b0 | 610 | if (!IS_ERR(child) && !child->d_inode) |
576bb263 | 611 | child = ovl_create_real(ofs, parent->d_inode, child, |
c86243b0 VG |
612 | OVL_CATTR(mode)); |
613 | inode_unlock(parent->d_inode); | |
614 | dput(parent); | |
615 | ||
616 | return child; | |
617 | } | |
618 | ||
619 | /* | |
620 | * Creates $workdir/work/incompat/volatile/dirty file if it is not already | |
621 | * present. | |
622 | */ | |
623 | static int ovl_create_volatile_dirty(struct ovl_fs *ofs) | |
624 | { | |
625 | unsigned int ctr; | |
626 | struct dentry *d = dget(ofs->workbasedir); | |
627 | static const char *const volatile_path[] = { | |
628 | OVL_WORKDIR_NAME, "incompat", "volatile", "dirty" | |
629 | }; | |
630 | const char *const *name = volatile_path; | |
631 | ||
632 | for (ctr = ARRAY_SIZE(volatile_path); ctr; ctr--, name++) { | |
576bb263 | 633 | d = ovl_lookup_or_create(ofs, d, *name, ctr > 1 ? S_IFDIR : S_IFREG); |
c86243b0 VG |
634 | if (IS_ERR(d)) |
635 | return PTR_ERR(d); | |
636 | } | |
637 | dput(d); | |
638 | return 0; | |
639 | } | |
640 | ||
146d62e5 | 641 | static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs, |
2d343087 | 642 | const struct path *workpath) |
8ed61dc3 | 643 | { |
08f4c7c8 | 644 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
2b1a7746 MS |
645 | struct dentry *workdir; |
646 | struct file *tmpfile; | |
d80172c2 AG |
647 | bool rename_whiteout; |
648 | bool d_type; | |
e487d889 | 649 | int fh_type; |
8ed61dc3 MS |
650 | int err; |
651 | ||
2ba9d57e AG |
652 | err = mnt_want_write(mnt); |
653 | if (err) | |
654 | return err; | |
655 | ||
235ce9ed AG |
656 | workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false); |
657 | err = PTR_ERR(workdir); | |
658 | if (IS_ERR_OR_NULL(workdir)) | |
2ba9d57e | 659 | goto out; |
8ed61dc3 | 660 | |
235ce9ed AG |
661 | ofs->workdir = workdir; |
662 | ||
146d62e5 AG |
663 | err = ovl_setup_trap(sb, ofs->workdir, &ofs->workdir_trap, "workdir"); |
664 | if (err) | |
665 | goto out; | |
666 | ||
8ed61dc3 MS |
667 | /* |
668 | * Upper should support d_type, else whiteouts are visible. Given | |
669 | * workdir and upper are on same fs, we can do iterate_dir() on | |
670 | * workdir. This check requires successful creation of workdir in | |
671 | * previous step. | |
672 | */ | |
673 | err = ovl_check_d_type_supported(workpath); | |
674 | if (err < 0) | |
2ba9d57e | 675 | goto out; |
8ed61dc3 | 676 | |
d80172c2 AG |
677 | d_type = err; |
678 | if (!d_type) | |
1bd0a3ae | 679 | pr_warn("upper fs needs to support d_type.\n"); |
8ed61dc3 MS |
680 | |
681 | /* Check if upper/work fs supports O_TMPFILE */ | |
2b1a7746 MS |
682 | tmpfile = ovl_do_tmpfile(ofs, ofs->workdir, S_IFREG | 0); |
683 | ofs->tmpfile = !IS_ERR(tmpfile); | |
ad204488 | 684 | if (ofs->tmpfile) |
2b1a7746 | 685 | fput(tmpfile); |
8ed61dc3 | 686 | else |
1bd0a3ae | 687 | pr_warn("upper fs does not support tmpfile.\n"); |
8ed61dc3 | 688 | |
cad218ab AG |
689 | |
690 | /* Check if upper/work fs supports RENAME_WHITEOUT */ | |
576bb263 | 691 | err = ovl_check_rename_whiteout(ofs); |
cad218ab AG |
692 | if (err < 0) |
693 | goto out; | |
694 | ||
d80172c2 AG |
695 | rename_whiteout = err; |
696 | if (!rename_whiteout) | |
cad218ab AG |
697 | pr_warn("upper fs does not support RENAME_WHITEOUT.\n"); |
698 | ||
8ed61dc3 | 699 | /* |
2d2f2d73 | 700 | * Check if upper/work fs supports (trusted|user).overlay.* xattr |
8ed61dc3 | 701 | */ |
c914c0e2 | 702 | err = ovl_setxattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE, "0", 1); |
8ed61dc3 | 703 | if (err) { |
b10b85fe | 704 | pr_warn("failed to set xattr on upper\n"); |
ad204488 | 705 | ofs->noxattr = true; |
af5f2396 AG |
706 | if (ovl_redirect_follow(ofs)) { |
707 | ofs->config.redirect_mode = OVL_REDIRECT_NOFOLLOW; | |
708 | pr_warn("...falling back to redirect_dir=nofollow.\n"); | |
709 | } | |
710 | if (ofs->config.metacopy) { | |
b0e0f697 | 711 | ofs->config.metacopy = false; |
af5f2396 AG |
712 | pr_warn("...falling back to metacopy=off.\n"); |
713 | } | |
714 | if (ofs->config.index) { | |
715 | ofs->config.index = false; | |
716 | pr_warn("...falling back to index=off.\n"); | |
b0e0f697 | 717 | } |
d9544c1b AG |
718 | if (ovl_has_fsid(ofs)) { |
719 | ofs->config.uuid = OVL_UUID_NULL; | |
720 | pr_warn("...falling back to uuid=null.\n"); | |
721 | } | |
b0e0f697 AG |
722 | /* |
723 | * xattr support is required for persistent st_ino. | |
724 | * Without persistent st_ino, xino=auto falls back to xino=off. | |
725 | */ | |
726 | if (ofs->config.xino == OVL_XINO_AUTO) { | |
727 | ofs->config.xino = OVL_XINO_OFF; | |
b10b85fe | 728 | pr_warn("...falling back to xino=off.\n"); |
b0e0f697 | 729 | } |
b10b85fe MS |
730 | if (err == -EPERM && !ofs->config.userxattr) |
731 | pr_info("try mounting with 'userxattr' option\n"); | |
2ba9d57e | 732 | err = 0; |
8ed61dc3 | 733 | } else { |
c914c0e2 | 734 | ovl_removexattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE); |
8ed61dc3 MS |
735 | } |
736 | ||
d80172c2 AG |
737 | /* |
738 | * We allowed sub-optimal upper fs configuration and don't want to break | |
739 | * users over kernel upgrade, but we never allowed remote upper fs, so | |
740 | * we can enforce strict requirements for remote upper fs. | |
741 | */ | |
742 | if (ovl_dentry_remote(ofs->workdir) && | |
743 | (!d_type || !rename_whiteout || ofs->noxattr)) { | |
744 | pr_err("upper fs missing required features.\n"); | |
745 | err = -EINVAL; | |
746 | goto out; | |
747 | } | |
748 | ||
c86243b0 VG |
749 | /* |
750 | * For volatile mount, create a incompat/volatile/dirty file to keep | |
751 | * track of it. | |
752 | */ | |
753 | if (ofs->config.ovl_volatile) { | |
754 | err = ovl_create_volatile_dirty(ofs); | |
755 | if (err < 0) { | |
756 | pr_err("Failed to create volatile/dirty file.\n"); | |
757 | goto out; | |
758 | } | |
759 | } | |
760 | ||
8ed61dc3 | 761 | /* Check if upper/work fs supports file handles */ |
e487d889 AG |
762 | fh_type = ovl_can_decode_fh(ofs->workdir->d_sb); |
763 | if (ofs->config.index && !fh_type) { | |
ad204488 | 764 | ofs->config.index = false; |
1bd0a3ae | 765 | pr_warn("upper fs does not support file handles, falling back to index=off.\n"); |
8ed61dc3 | 766 | } |
16aac5ad | 767 | ofs->nofh |= !fh_type; |
8ed61dc3 | 768 | |
e487d889 AG |
769 | /* Check if upper fs has 32bit inode numbers */ |
770 | if (fh_type != FILEID_INO32_GEN) | |
0f831ec8 | 771 | ofs->xino_mode = -1; |
e487d889 | 772 | |
f168f109 AG |
773 | /* NFS export of r/w mount depends on index */ |
774 | if (ofs->config.nfs_export && !ofs->config.index) { | |
1bd0a3ae | 775 | pr_warn("NFS export requires \"index=on\", falling back to nfs_export=off.\n"); |
f168f109 AG |
776 | ofs->config.nfs_export = false; |
777 | } | |
2ba9d57e AG |
778 | out: |
779 | mnt_drop_write(mnt); | |
780 | return err; | |
8ed61dc3 MS |
781 | } |
782 | ||
146d62e5 | 783 | static int ovl_get_workdir(struct super_block *sb, struct ovl_fs *ofs, |
b36a5780 CB |
784 | const struct path *upperpath, |
785 | const struct path *workpath) | |
520d7c86 MS |
786 | { |
787 | int err; | |
520d7c86 MS |
788 | |
789 | err = -EINVAL; | |
b36a5780 | 790 | if (upperpath->mnt != workpath->mnt) { |
1bd0a3ae | 791 | pr_err("workdir and upperdir must reside under the same mount\n"); |
b36a5780 | 792 | return err; |
520d7c86 | 793 | } |
b36a5780 | 794 | if (!ovl_workdir_ok(workpath->dentry, upperpath->dentry)) { |
1bd0a3ae | 795 | pr_err("workdir and upperdir must be separate subtrees\n"); |
b36a5780 | 796 | return err; |
520d7c86 MS |
797 | } |
798 | ||
b36a5780 | 799 | ofs->workbasedir = dget(workpath->dentry); |
8c25741a | 800 | |
8c25741a | 801 | if (ovl_inuse_trylock(ofs->workbasedir)) { |
ad204488 | 802 | ofs->workdir_locked = true; |
520d7c86 | 803 | } else { |
0be0bfd2 AG |
804 | err = ovl_report_in_use(ofs, "workdir"); |
805 | if (err) | |
b36a5780 | 806 | return err; |
520d7c86 MS |
807 | } |
808 | ||
0be0bfd2 AG |
809 | err = ovl_setup_trap(sb, ofs->workbasedir, &ofs->workbasedir_trap, |
810 | "workdir"); | |
811 | if (err) | |
b36a5780 | 812 | return err; |
bca44b52 | 813 | |
b36a5780 | 814 | return ovl_make_workdir(sb, ofs, workpath); |
520d7c86 MS |
815 | } |
816 | ||
146d62e5 | 817 | static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, |
2d343087 | 818 | struct ovl_entry *oe, const struct path *upperpath) |
f7e3a7d9 | 819 | { |
08f4c7c8 | 820 | struct vfsmount *mnt = ovl_upper_mnt(ofs); |
235ce9ed | 821 | struct dentry *indexdir; |
5b02bfc1 AG |
822 | struct dentry *origin = ovl_lowerstack(oe)->dentry; |
823 | const struct ovl_fh *fh; | |
f7e3a7d9 MS |
824 | int err; |
825 | ||
5b02bfc1 AG |
826 | fh = ovl_get_origin_fh(ofs, origin); |
827 | if (IS_ERR(fh)) | |
828 | return PTR_ERR(fh); | |
829 | ||
2ba9d57e AG |
830 | err = mnt_want_write(mnt); |
831 | if (err) | |
5b02bfc1 | 832 | goto out_free_fh; |
2ba9d57e | 833 | |
f7e3a7d9 | 834 | /* Verify lower root is upper root origin */ |
5b02bfc1 | 835 | err = ovl_verify_origin_fh(ofs, upperpath->dentry, fh, true); |
f7e3a7d9 | 836 | if (err) { |
1bd0a3ae | 837 | pr_err("failed to verify upper root origin\n"); |
f7e3a7d9 MS |
838 | goto out; |
839 | } | |
840 | ||
470c1563 AG |
841 | /* index dir will act also as workdir */ |
842 | iput(ofs->workdir_trap); | |
843 | ofs->workdir_trap = NULL; | |
844 | dput(ofs->workdir); | |
845 | ofs->workdir = NULL; | |
235ce9ed AG |
846 | indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true); |
847 | if (IS_ERR(indexdir)) { | |
848 | err = PTR_ERR(indexdir); | |
849 | } else if (indexdir) { | |
02d70090 AG |
850 | ofs->workdir = indexdir; |
851 | err = ovl_setup_trap(sb, indexdir, &ofs->workdir_trap, | |
146d62e5 AG |
852 | "indexdir"); |
853 | if (err) | |
854 | goto out; | |
855 | ||
ad1d615c AG |
856 | /* |
857 | * Verify upper root is exclusively associated with index dir. | |
2d2f2d73 | 858 | * Older kernels stored upper fh in ".overlay.origin" |
ad1d615c AG |
859 | * xattr. If that xattr exists, verify that it is a match to |
860 | * upper dir file handle. In any case, verify or set xattr | |
2d2f2d73 | 861 | * ".overlay.upper" to indicate that index may have |
ad1d615c AG |
862 | * directory entries. |
863 | */ | |
02d70090 AG |
864 | if (ovl_check_origin_xattr(ofs, indexdir)) { |
865 | err = ovl_verify_origin_xattr(ofs, indexdir, | |
5b02bfc1 AG |
866 | OVL_XATTR_ORIGIN, |
867 | upperpath->dentry, true, | |
868 | false); | |
ad1d615c | 869 | if (err) |
1bd0a3ae | 870 | pr_err("failed to verify index dir 'origin' xattr\n"); |
ad1d615c | 871 | } |
02d70090 | 872 | err = ovl_verify_upper(ofs, indexdir, upperpath->dentry, true); |
f7e3a7d9 | 873 | if (err) |
1bd0a3ae | 874 | pr_err("failed to verify index dir 'upper' xattr\n"); |
f7e3a7d9 MS |
875 | |
876 | /* Cleanup bad/stale/orphan index entries */ | |
877 | if (!err) | |
1eff1a1d | 878 | err = ovl_indexdir_cleanup(ofs); |
f7e3a7d9 | 879 | } |
02d70090 | 880 | if (err || !indexdir) |
1bd0a3ae | 881 | pr_warn("try deleting index dir or mounting with '-o index=off' to disable inodes index.\n"); |
f7e3a7d9 MS |
882 | |
883 | out: | |
2ba9d57e | 884 | mnt_drop_write(mnt); |
5b02bfc1 AG |
885 | out_free_fh: |
886 | kfree(fh); | |
f7e3a7d9 MS |
887 | return err; |
888 | } | |
889 | ||
9df085f3 AG |
890 | static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid) |
891 | { | |
892 | unsigned int i; | |
893 | ||
08f4c7c8 | 894 | if (!ofs->config.nfs_export && !ovl_upper_mnt(ofs)) |
9df085f3 AG |
895 | return true; |
896 | ||
a888db31 AG |
897 | /* |
898 | * We allow using single lower with null uuid for index and nfs_export | |
899 | * for example to support those features with single lower squashfs. | |
900 | * To avoid regressions in setups of overlay with re-formatted lower | |
901 | * squashfs, do not allow decoding origin with lower null uuid unless | |
902 | * user opted-in to one of the new features that require following the | |
903 | * lower inode of non-dir upper. | |
904 | */ | |
ca45275c | 905 | if (ovl_allow_offline_changes(ofs) && uuid_is_null(uuid)) |
a888db31 AG |
906 | return false; |
907 | ||
1b81dddd | 908 | for (i = 0; i < ofs->numfs; i++) { |
9df085f3 AG |
909 | /* |
910 | * We use uuid to associate an overlay lower file handle with a | |
911 | * lower layer, so we can accept lower fs with null uuid as long | |
912 | * as all lower layers with null uuid are on the same fs. | |
7e63c87f AG |
913 | * if we detect multiple lower fs with the same uuid, we |
914 | * disable lower file handle decoding on all of them. | |
9df085f3 | 915 | */ |
1b81dddd AG |
916 | if (ofs->fs[i].is_lower && |
917 | uuid_equal(&ofs->fs[i].sb->s_uuid, uuid)) { | |
07f1e596 | 918 | ofs->fs[i].bad_uuid = true; |
9df085f3 | 919 | return false; |
7e63c87f | 920 | } |
9df085f3 AG |
921 | } |
922 | return true; | |
923 | } | |
924 | ||
5148626b | 925 | /* Get a unique fsid for the layer */ |
9df085f3 | 926 | static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path) |
5148626b | 927 | { |
9df085f3 | 928 | struct super_block *sb = path->mnt->mnt_sb; |
5148626b AG |
929 | unsigned int i; |
930 | dev_t dev; | |
931 | int err; | |
7e63c87f | 932 | bool bad_uuid = false; |
b0e0f697 | 933 | bool warn = false; |
5148626b | 934 | |
07f1e596 AG |
935 | for (i = 0; i < ofs->numfs; i++) { |
936 | if (ofs->fs[i].sb == sb) | |
937 | return i; | |
5148626b AG |
938 | } |
939 | ||
9df085f3 | 940 | if (!ovl_lower_uuid_ok(ofs, &sb->s_uuid)) { |
7e63c87f | 941 | bad_uuid = true; |
b0e0f697 AG |
942 | if (ofs->config.xino == OVL_XINO_AUTO) { |
943 | ofs->config.xino = OVL_XINO_OFF; | |
944 | warn = true; | |
945 | } | |
7e63c87f AG |
946 | if (ofs->config.index || ofs->config.nfs_export) { |
947 | ofs->config.index = false; | |
948 | ofs->config.nfs_export = false; | |
b0e0f697 AG |
949 | warn = true; |
950 | } | |
951 | if (warn) { | |
952 | pr_warn("%s uuid detected in lower fs '%pd2', falling back to xino=%s,index=off,nfs_export=off.\n", | |
7e63c87f AG |
953 | uuid_is_null(&sb->s_uuid) ? "null" : |
954 | "conflicting", | |
dcb399de | 955 | path->dentry, ovl_xino_mode(&ofs->config)); |
7e63c87f | 956 | } |
9df085f3 AG |
957 | } |
958 | ||
5148626b AG |
959 | err = get_anon_bdev(&dev); |
960 | if (err) { | |
1bd0a3ae | 961 | pr_err("failed to get anonymous bdev for lowerpath\n"); |
5148626b AG |
962 | return err; |
963 | } | |
964 | ||
07f1e596 AG |
965 | ofs->fs[ofs->numfs].sb = sb; |
966 | ofs->fs[ofs->numfs].pseudo_dev = dev; | |
967 | ofs->fs[ofs->numfs].bad_uuid = bad_uuid; | |
5148626b | 968 | |
07f1e596 | 969 | return ofs->numfs++; |
5148626b AG |
970 | } |
971 | ||
37ebf056 AG |
972 | /* |
973 | * The fsid after the last lower fsid is used for the data layers. | |
974 | * It is a "null fs" with a null sb, null uuid, and no pseudo dev. | |
975 | */ | |
976 | static int ovl_get_data_fsid(struct ovl_fs *ofs) | |
977 | { | |
978 | return ofs->numfs; | |
979 | } | |
980 | ||
981 | ||
94375f9d | 982 | static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, |
b36a5780 | 983 | struct ovl_fs_context *ctx, struct ovl_layer *layers) |
520d7c86 MS |
984 | { |
985 | int err; | |
986 | unsigned int i; | |
b36a5780 | 987 | size_t nr_merged_lower; |
520d7c86 | 988 | |
b36a5780 | 989 | ofs->fs = kcalloc(ctx->nr + 2, sizeof(struct ovl_sb), GFP_KERNEL); |
07f1e596 | 990 | if (ofs->fs == NULL) |
9e88f905 | 991 | return -ENOMEM; |
5148626b | 992 | |
37ebf056 AG |
993 | /* |
994 | * idx/fsid 0 are reserved for upper fs even with lower only overlay | |
995 | * and the last fsid is reserved for "null fs" of the data layers. | |
996 | */ | |
07f1e596 AG |
997 | ofs->numfs++; |
998 | ||
07f1e596 | 999 | /* |
b7bf9908 AG |
1000 | * All lower layers that share the same fs as upper layer, use the same |
1001 | * pseudo_dev as upper layer. Allocate fs[0].pseudo_dev even for lower | |
1002 | * only overlay to simplify ovl_fs_free(). | |
1b81dddd | 1003 | * is_lower will be set if upper fs is shared with a lower layer. |
07f1e596 | 1004 | */ |
b7bf9908 AG |
1005 | err = get_anon_bdev(&ofs->fs[0].pseudo_dev); |
1006 | if (err) { | |
1007 | pr_err("failed to get anonymous bdev for upper fs\n"); | |
9e88f905 | 1008 | return err; |
b7bf9908 AG |
1009 | } |
1010 | ||
08f4c7c8 MS |
1011 | if (ovl_upper_mnt(ofs)) { |
1012 | ofs->fs[0].sb = ovl_upper_mnt(ofs)->mnt_sb; | |
1b81dddd | 1013 | ofs->fs[0].is_lower = false; |
07f1e596 AG |
1014 | } |
1015 | ||
b36a5780 CB |
1016 | nr_merged_lower = ctx->nr - ctx->nr_data; |
1017 | for (i = 0; i < ctx->nr; i++) { | |
1018 | struct ovl_fs_context_layer *l = &ctx->lower[i]; | |
520d7c86 | 1019 | struct vfsmount *mnt; |
146d62e5 | 1020 | struct inode *trap; |
5148626b | 1021 | int fsid; |
520d7c86 | 1022 | |
b36a5780 CB |
1023 | if (i < nr_merged_lower) |
1024 | fsid = ovl_get_fsid(ofs, &l->path); | |
37ebf056 AG |
1025 | else |
1026 | fsid = ovl_get_data_fsid(ofs); | |
9e88f905 AG |
1027 | if (fsid < 0) |
1028 | return fsid; | |
520d7c86 | 1029 | |
24f14009 | 1030 | /* |
1031 | * Check if lower root conflicts with this overlay layers before | |
1032 | * checking if it is in-use as upperdir/workdir of "another" | |
1033 | * mount, because we do not bother to check in ovl_is_inuse() if | |
1034 | * the upperdir/workdir is in fact in-use by our | |
1035 | * upperdir/workdir. | |
1036 | */ | |
b36a5780 | 1037 | err = ovl_setup_trap(sb, l->path.dentry, &trap, "lowerdir"); |
146d62e5 | 1038 | if (err) |
9e88f905 | 1039 | return err; |
146d62e5 | 1040 | |
b36a5780 | 1041 | if (ovl_is_inuse(l->path.dentry)) { |
0be0bfd2 | 1042 | err = ovl_report_in_use(ofs, "lowerdir"); |
24f14009 | 1043 | if (err) { |
1044 | iput(trap); | |
9e88f905 | 1045 | return err; |
24f14009 | 1046 | } |
0be0bfd2 AG |
1047 | } |
1048 | ||
b36a5780 | 1049 | mnt = clone_private_mount(&l->path); |
520d7c86 MS |
1050 | err = PTR_ERR(mnt); |
1051 | if (IS_ERR(mnt)) { | |
1bd0a3ae | 1052 | pr_err("failed to clone lowerpath\n"); |
146d62e5 | 1053 | iput(trap); |
9e88f905 | 1054 | return err; |
520d7c86 | 1055 | } |
5148626b | 1056 | |
520d7c86 MS |
1057 | /* |
1058 | * Make lower layers R/O. That way fchmod/fchown on lower file | |
1059 | * will fail instead of modifying lower fs. | |
1060 | */ | |
1061 | mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME; | |
1062 | ||
13464165 MS |
1063 | layers[ofs->numlayer].trap = trap; |
1064 | layers[ofs->numlayer].mnt = mnt; | |
1065 | layers[ofs->numlayer].idx = ofs->numlayer; | |
1066 | layers[ofs->numlayer].fsid = fsid; | |
1067 | layers[ofs->numlayer].fs = &ofs->fs[fsid]; | |
a535116d AG |
1068 | /* Store for printing lowerdir=... in ovl_show_options() */ |
1069 | ofs->config.lowerdirs[ofs->numlayer] = l->name; | |
b36a5780 | 1070 | l->name = NULL; |
94375f9d | 1071 | ofs->numlayer++; |
1b81dddd | 1072 | ofs->fs[fsid].is_lower = true; |
520d7c86 | 1073 | } |
e487d889 | 1074 | |
795939a9 AG |
1075 | /* |
1076 | * When all layers on same fs, overlay can use real inode numbers. | |
926e94d7 AG |
1077 | * With mount option "xino=<on|auto>", mounter declares that there are |
1078 | * enough free high bits in underlying fs to hold the unique fsid. | |
795939a9 AG |
1079 | * If overlayfs does encounter underlying inodes using the high xino |
1080 | * bits reserved for fsid, it emits a warning and uses the original | |
dfe51d47 AG |
1081 | * inode number or a non persistent inode number allocated from a |
1082 | * dedicated range. | |
795939a9 | 1083 | */ |
08f4c7c8 | 1084 | if (ofs->numfs - !ovl_upper_mnt(ofs) == 1) { |
0f831ec8 AG |
1085 | if (ofs->config.xino == OVL_XINO_ON) |
1086 | pr_info("\"xino=on\" is useless with all layers on same fs, ignore.\n"); | |
1087 | ofs->xino_mode = 0; | |
53afcd31 AG |
1088 | } else if (ofs->config.xino == OVL_XINO_OFF) { |
1089 | ofs->xino_mode = -1; | |
926e94d7 | 1090 | } else if (ofs->xino_mode < 0) { |
795939a9 | 1091 | /* |
07f1e596 | 1092 | * This is a roundup of number of bits needed for encoding |
dfe51d47 AG |
1093 | * fsid, where fsid 0 is reserved for upper fs (even with |
1094 | * lower only overlay) +1 extra bit is reserved for the non | |
1095 | * persistent inode number range that is used for resolving | |
1096 | * xino lower bits overflow. | |
795939a9 | 1097 | */ |
dfe51d47 AG |
1098 | BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 30); |
1099 | ofs->xino_mode = ilog2(ofs->numfs - 1) + 2; | |
795939a9 AG |
1100 | } |
1101 | ||
0f831ec8 | 1102 | if (ofs->xino_mode > 0) { |
1bd0a3ae | 1103 | pr_info("\"xino\" feature enabled using %d upper inode bits.\n", |
0f831ec8 | 1104 | ofs->xino_mode); |
795939a9 | 1105 | } |
e487d889 | 1106 | |
9e88f905 | 1107 | return 0; |
520d7c86 MS |
1108 | } |
1109 | ||
4155c10a | 1110 | static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, |
b36a5780 CB |
1111 | struct ovl_fs_context *ctx, |
1112 | struct ovl_fs *ofs, | |
1113 | struct ovl_layer *layers) | |
53dbb0b4 MS |
1114 | { |
1115 | int err; | |
b8e42a65 | 1116 | unsigned int i; |
b36a5780 | 1117 | size_t nr_merged_lower; |
4155c10a | 1118 | struct ovl_entry *oe; |
b36a5780 CB |
1119 | struct ovl_path *lowerstack; |
1120 | ||
1121 | struct ovl_fs_context_layer *l; | |
53dbb0b4 | 1122 | |
b36a5780 | 1123 | if (!ofs->config.upperdir && ctx->nr == 1) { |
1bd0a3ae | 1124 | pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n"); |
b8e42a65 | 1125 | return ERR_PTR(-EINVAL); |
53dbb0b4 MS |
1126 | } |
1127 | ||
b36a5780 CB |
1128 | err = -EINVAL; |
1129 | for (i = 0; i < ctx->nr; i++) { | |
1130 | l = &ctx->lower[i]; | |
53dbb0b4 | 1131 | |
b36a5780 | 1132 | err = ovl_lower_dir(l->name, &l->path, ofs, &sb->s_stack_depth); |
53dbb0b4 | 1133 | if (err) |
b36a5780 | 1134 | return ERR_PTR(err); |
53dbb0b4 MS |
1135 | } |
1136 | ||
1137 | err = -EINVAL; | |
1138 | sb->s_stack_depth++; | |
1139 | if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { | |
1bd0a3ae | 1140 | pr_err("maximum fs stacking depth exceeded\n"); |
b36a5780 | 1141 | return ERR_PTR(err); |
53dbb0b4 MS |
1142 | } |
1143 | ||
b36a5780 | 1144 | err = ovl_get_layers(sb, ofs, ctx, layers); |
4155c10a | 1145 | if (err) |
b36a5780 | 1146 | return ERR_PTR(err); |
4155c10a MS |
1147 | |
1148 | err = -ENOMEM; | |
37ebf056 | 1149 | /* Data-only layers are not merged in root directory */ |
b36a5780 CB |
1150 | nr_merged_lower = ctx->nr - ctx->nr_data; |
1151 | oe = ovl_alloc_entry(nr_merged_lower); | |
4155c10a | 1152 | if (!oe) |
b36a5780 | 1153 | return ERR_PTR(err); |
4155c10a | 1154 | |
5522c9c7 | 1155 | lowerstack = ovl_lowerstack(oe); |
b36a5780 CB |
1156 | for (i = 0; i < nr_merged_lower; i++) { |
1157 | l = &ctx->lower[i]; | |
1158 | lowerstack[i].dentry = dget(l->path.dentry); | |
1159 | lowerstack[i].layer = &ofs->layers[i + 1]; | |
4155c10a | 1160 | } |
b36a5780 | 1161 | ofs->numdatalayer = ctx->nr_data; |
4155c10a MS |
1162 | |
1163 | return oe; | |
53dbb0b4 MS |
1164 | } |
1165 | ||
146d62e5 AG |
1166 | /* |
1167 | * Check if this layer root is a descendant of: | |
1168 | * - another layer of this overlayfs instance | |
1169 | * - upper/work dir of any overlayfs instance | |
146d62e5 | 1170 | */ |
0be0bfd2 | 1171 | static int ovl_check_layer(struct super_block *sb, struct ovl_fs *ofs, |
708fa015 MS |
1172 | struct dentry *dentry, const char *name, |
1173 | bool is_lower) | |
146d62e5 | 1174 | { |
9179c21d | 1175 | struct dentry *next = dentry, *parent; |
146d62e5 AG |
1176 | int err = 0; |
1177 | ||
9179c21d | 1178 | if (!dentry) |
146d62e5 AG |
1179 | return 0; |
1180 | ||
9179c21d MS |
1181 | parent = dget_parent(next); |
1182 | ||
1183 | /* Walk back ancestors to root (inclusive) looking for traps */ | |
1184 | while (!err && parent != next) { | |
708fa015 | 1185 | if (is_lower && ovl_lookup_trap_inode(sb, parent)) { |
146d62e5 | 1186 | err = -ELOOP; |
1bd0a3ae | 1187 | pr_err("overlapping %s path\n", name); |
0be0bfd2 AG |
1188 | } else if (ovl_is_inuse(parent)) { |
1189 | err = ovl_report_in_use(ofs, name); | |
146d62e5 | 1190 | } |
146d62e5 | 1191 | next = parent; |
9179c21d MS |
1192 | parent = dget_parent(next); |
1193 | dput(next); | |
146d62e5 AG |
1194 | } |
1195 | ||
9179c21d | 1196 | dput(parent); |
146d62e5 AG |
1197 | |
1198 | return err; | |
1199 | } | |
1200 | ||
1201 | /* | |
1202 | * Check if any of the layers or work dirs overlap. | |
1203 | */ | |
1204 | static int ovl_check_overlapping_layers(struct super_block *sb, | |
1205 | struct ovl_fs *ofs) | |
1206 | { | |
1207 | int i, err; | |
1208 | ||
08f4c7c8 MS |
1209 | if (ovl_upper_mnt(ofs)) { |
1210 | err = ovl_check_layer(sb, ofs, ovl_upper_mnt(ofs)->mnt_root, | |
708fa015 | 1211 | "upperdir", false); |
146d62e5 AG |
1212 | if (err) |
1213 | return err; | |
1214 | ||
1215 | /* | |
1216 | * Checking workbasedir avoids hitting ovl_is_inuse(parent) of | |
1217 | * this instance and covers overlapping work and index dirs, | |
1218 | * unless work or index dir have been moved since created inside | |
1219 | * workbasedir. In that case, we already have their traps in | |
1220 | * inode cache and we will catch that case on lookup. | |
1221 | */ | |
708fa015 MS |
1222 | err = ovl_check_layer(sb, ofs, ofs->workbasedir, "workdir", |
1223 | false); | |
146d62e5 AG |
1224 | if (err) |
1225 | return err; | |
1226 | } | |
1227 | ||
94375f9d | 1228 | for (i = 1; i < ofs->numlayer; i++) { |
0be0bfd2 | 1229 | err = ovl_check_layer(sb, ofs, |
94375f9d | 1230 | ofs->layers[i].mnt->mnt_root, |
708fa015 | 1231 | "lowerdir", true); |
146d62e5 AG |
1232 | if (err) |
1233 | return err; | |
1234 | } | |
1235 | ||
1236 | return 0; | |
1237 | } | |
1238 | ||
2effc5c2 AG |
1239 | static struct dentry *ovl_get_root(struct super_block *sb, |
1240 | struct dentry *upperdentry, | |
1241 | struct ovl_entry *oe) | |
1242 | { | |
1243 | struct dentry *root; | |
420332b9 | 1244 | struct ovl_fs *ofs = OVL_FS(sb); |
5522c9c7 | 1245 | struct ovl_path *lowerpath = ovl_lowerstack(oe); |
62c832ed AG |
1246 | unsigned long ino = d_inode(lowerpath->dentry)->i_ino; |
1247 | int fsid = lowerpath->layer->fsid; | |
1248 | struct ovl_inode_params oip = { | |
1249 | .upperdentry = upperdentry, | |
0af950f5 | 1250 | .oe = oe, |
62c832ed | 1251 | }; |
2effc5c2 AG |
1252 | |
1253 | root = d_make_root(ovl_new_inode(sb, S_IFDIR, 0)); | |
1254 | if (!root) | |
1255 | return NULL; | |
1256 | ||
2effc5c2 | 1257 | if (upperdentry) { |
62c832ed AG |
1258 | /* Root inode uses upper st_ino/i_ino */ |
1259 | ino = d_inode(upperdentry)->i_ino; | |
1260 | fsid = 0; | |
2effc5c2 | 1261 | ovl_dentry_set_upper_alias(root); |
610afc0b | 1262 | if (ovl_is_impuredir(sb, upperdentry)) |
2effc5c2 AG |
1263 | ovl_set_flag(OVL_IMPURE, d_inode(root)); |
1264 | } | |
1265 | ||
420332b9 AG |
1266 | /* Look for xwhiteouts marker except in the lowermost layer */ |
1267 | for (int i = 0; i < ovl_numlower(oe) - 1; i++, lowerpath++) { | |
1268 | struct path path = { | |
1269 | .mnt = lowerpath->layer->mnt, | |
1270 | .dentry = lowerpath->dentry, | |
1271 | }; | |
1272 | ||
1273 | /* overlay.opaque=x means xwhiteouts directory */ | |
1274 | if (ovl_get_opaquedir_val(ofs, &path) == 'x') { | |
1275 | ovl_layer_set_xwhiteouts(ofs, lowerpath->layer); | |
1276 | ovl_dentry_set_xwhiteouts(root); | |
1277 | } | |
1278 | } | |
1279 | ||
2effc5c2 AG |
1280 | /* Root is always merge -> can have whiteouts */ |
1281 | ovl_set_flag(OVL_WHITEOUTS, d_inode(root)); | |
1282 | ovl_dentry_set_flag(OVL_E_CONNECTED, root); | |
1283 | ovl_set_upperdata(d_inode(root)); | |
62c832ed | 1284 | ovl_inode_init(d_inode(root), &oip, ino, fsid); |
0af950f5 | 1285 | ovl_dentry_init_flags(root, upperdentry, oe, DCACHE_OP_WEAK_REVALIDATE); |
367d002d AG |
1286 | /* root keeps a reference of upperdentry */ |
1287 | dget(upperdentry); | |
2effc5c2 AG |
1288 | |
1289 | return root; | |
1290 | } | |
1291 | ||
7fb7998b | 1292 | int ovl_fill_super(struct super_block *sb, struct fs_context *fc) |
e9be9d5e | 1293 | { |
1784fbc2 CB |
1294 | struct ovl_fs *ofs = sb->s_fs_info; |
1295 | struct ovl_fs_context *ctx = fc->fs_private; | |
e9be9d5e | 1296 | struct dentry *root_dentry; |
4155c10a | 1297 | struct ovl_entry *oe; |
b8e42a65 | 1298 | struct ovl_layer *layers; |
51f8f3c4 | 1299 | struct cred *cred; |
e9be9d5e MS |
1300 | int err; |
1301 | ||
9efb069d | 1302 | err = -EIO; |
1784fbc2 CB |
1303 | if (WARN_ON(fc->user_ns != current_user_ns())) |
1304 | goto out_err; | |
9efb069d | 1305 | |
f4288844 MS |
1306 | sb->s_d_op = &ovl_dentry_operations; |
1307 | ||
d7b49b10 | 1308 | err = -ENOMEM; |
ad204488 | 1309 | ofs->creator_cred = cred = prepare_creds(); |
c6fe6254 MS |
1310 | if (!cred) |
1311 | goto out_err; | |
1312 | ||
1784fbc2 | 1313 | err = ovl_fs_params_verify(ctx, &ofs->config); |
f45827e8 | 1314 | if (err) |
a9075cdb | 1315 | goto out_err; |
f45827e8 | 1316 | |
e9be9d5e | 1317 | err = -EINVAL; |
b36a5780 | 1318 | if (ctx->nr == 0) { |
1784fbc2 | 1319 | if (!(fc->sb_flags & SB_SILENT)) |
1bd0a3ae | 1320 | pr_err("missing 'lowerdir'\n"); |
a9075cdb | 1321 | goto out_err; |
e9be9d5e MS |
1322 | } |
1323 | ||
b8e42a65 | 1324 | err = -ENOMEM; |
b36a5780 | 1325 | layers = kcalloc(ctx->nr + 1, sizeof(struct ovl_layer), GFP_KERNEL); |
b8e42a65 MS |
1326 | if (!layers) |
1327 | goto out_err; | |
1328 | ||
a535116d AG |
1329 | ofs->config.lowerdirs = kcalloc(ctx->nr + 1, sizeof(char *), GFP_KERNEL); |
1330 | if (!ofs->config.lowerdirs) { | |
1331 | kfree(layers); | |
1332 | goto out_err; | |
1333 | } | |
b8e42a65 | 1334 | ofs->layers = layers; |
a535116d AG |
1335 | /* |
1336 | * Layer 0 is reserved for upper even if there's no upper. | |
0cea4c09 AG |
1337 | * config.lowerdirs[0] is used for storing the user provided colon |
1338 | * separated lowerdir string. | |
a535116d | 1339 | */ |
0cea4c09 AG |
1340 | ofs->config.lowerdirs[0] = ctx->lowerdir_all; |
1341 | ctx->lowerdir_all = NULL; | |
b8e42a65 MS |
1342 | ofs->numlayer = 1; |
1343 | ||
53a08cb9 | 1344 | sb->s_stack_depth = 0; |
cf9a6784 | 1345 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
4d314f78 | 1346 | atomic_long_set(&ofs->last_ino, 1); |
4f119628 | 1347 | /* Assume underlying fs uses 32bit inodes unless proven otherwise */ |
53afcd31 | 1348 | if (ofs->config.xino != OVL_XINO_OFF) { |
0f831ec8 | 1349 | ofs->xino_mode = BITS_PER_LONG - 32; |
53afcd31 AG |
1350 | if (!ofs->xino_mode) { |
1351 | pr_warn("xino not supported on 32bit kernel, falling back to xino=off.\n"); | |
1352 | ofs->config.xino = OVL_XINO_OFF; | |
1353 | } | |
1354 | } | |
795939a9 | 1355 | |
146d62e5 AG |
1356 | /* alloc/destroy_inode needed for setting up traps in inode cache */ |
1357 | sb->s_op = &ovl_super_operations; | |
1358 | ||
ad204488 | 1359 | if (ofs->config.upperdir) { |
335d3fc5 SD |
1360 | struct super_block *upper_sb; |
1361 | ||
d7b49b10 | 1362 | err = -EINVAL; |
ad204488 | 1363 | if (!ofs->config.workdir) { |
1bd0a3ae | 1364 | pr_err("missing 'workdir'\n"); |
a9075cdb | 1365 | goto out_err; |
53a08cb9 | 1366 | } |
e9be9d5e | 1367 | |
b36a5780 | 1368 | err = ovl_get_upper(sb, ofs, &layers[0], &ctx->upper); |
53a08cb9 | 1369 | if (err) |
a9075cdb | 1370 | goto out_err; |
2cac0c00 | 1371 | |
335d3fc5 SD |
1372 | upper_sb = ovl_upper_mnt(ofs)->mnt_sb; |
1373 | if (!ovl_should_sync(ofs)) { | |
1374 | ofs->errseq = errseq_sample(&upper_sb->s_wb_err); | |
1375 | if (errseq_check(&upper_sb->s_wb_err, ofs->errseq)) { | |
1376 | err = -EIO; | |
1377 | pr_err("Cannot mount volatile when upperdir has an unseen error. Sync upperdir fs to clear state.\n"); | |
1378 | goto out_err; | |
1379 | } | |
1380 | } | |
1381 | ||
b36a5780 | 1382 | err = ovl_get_workdir(sb, ofs, &ctx->upper, &ctx->work); |
8ed61dc3 | 1383 | if (err) |
a9075cdb | 1384 | goto out_err; |
c6fe6254 | 1385 | |
ad204488 | 1386 | if (!ofs->workdir) |
1751e8a6 | 1387 | sb->s_flags |= SB_RDONLY; |
6e88256e | 1388 | |
335d3fc5 SD |
1389 | sb->s_stack_depth = upper_sb->s_stack_depth; |
1390 | sb->s_time_gran = upper_sb->s_time_gran; | |
e9be9d5e | 1391 | } |
b36a5780 | 1392 | oe = ovl_get_lowerstack(sb, ctx, ofs, layers); |
4155c10a MS |
1393 | err = PTR_ERR(oe); |
1394 | if (IS_ERR(oe)) | |
a9075cdb | 1395 | goto out_err; |
e9be9d5e | 1396 | |
71cbad7e | 1397 | /* If the upper fs is nonexistent, we mark overlayfs r/o too */ |
08f4c7c8 | 1398 | if (!ovl_upper_mnt(ofs)) |
1751e8a6 | 1399 | sb->s_flags |= SB_RDONLY; |
e9be9d5e | 1400 | |
b0504bfe AG |
1401 | if (!ovl_origin_uuid(ofs) && ofs->numfs > 1) { |
1402 | pr_warn("The uuid=off requires a single fs for lower and upper, falling back to uuid=null.\n"); | |
1403 | ofs->config.uuid = OVL_UUID_NULL; | |
d9544c1b AG |
1404 | } else if (ovl_has_fsid(ofs) && ovl_upper_mnt(ofs)) { |
1405 | /* Use per instance persistent uuid/fsid */ | |
1406 | ovl_init_uuid_xattr(sb, ofs, &ctx->upper); | |
5830fb6b PT |
1407 | } |
1408 | ||
470c1563 | 1409 | if (!ovl_force_readonly(ofs) && ofs->config.index) { |
b36a5780 | 1410 | err = ovl_get_indexdir(sb, ofs, oe, &ctx->upper); |
54fb347e | 1411 | if (err) |
4155c10a | 1412 | goto out_free_oe; |
6e88256e | 1413 | |
972d0093 | 1414 | /* Force r/o mount with no index dir */ |
02d70090 | 1415 | if (!ofs->workdir) |
1751e8a6 | 1416 | sb->s_flags |= SB_RDONLY; |
02bcd157 AG |
1417 | } |
1418 | ||
146d62e5 AG |
1419 | err = ovl_check_overlapping_layers(sb, ofs); |
1420 | if (err) | |
1421 | goto out_free_oe; | |
1422 | ||
972d0093 | 1423 | /* Show index=off in /proc/mounts for forced r/o mount */ |
02d70090 | 1424 | if (!ofs->workdir) { |
ad204488 | 1425 | ofs->config.index = false; |
08f4c7c8 | 1426 | if (ovl_upper_mnt(ofs) && ofs->config.nfs_export) { |
1bd0a3ae | 1427 | pr_warn("NFS export requires an index dir, falling back to nfs_export=off.\n"); |
f168f109 AG |
1428 | ofs->config.nfs_export = false; |
1429 | } | |
1430 | } | |
02bcd157 | 1431 | |
d5791044 | 1432 | if (ofs->config.metacopy && ofs->config.nfs_export) { |
1bd0a3ae | 1433 | pr_warn("NFS export is not supported with metadata only copy up, falling back to nfs_export=off.\n"); |
d5791044 VG |
1434 | ofs->config.nfs_export = false; |
1435 | } | |
1436 | ||
16aac5ad AG |
1437 | /* |
1438 | * Support encoding decodable file handles with nfs_export=on | |
1439 | * and encoding non-decodable file handles with nfs_export=off | |
1440 | * if all layers support file handles. | |
1441 | */ | |
8383f174 AG |
1442 | if (ofs->config.nfs_export) |
1443 | sb->s_export_op = &ovl_export_operations; | |
16aac5ad AG |
1444 | else if (!ofs->nofh) |
1445 | sb->s_export_op = &ovl_export_fid_operations; | |
8383f174 | 1446 | |
51f8f3c4 KK |
1447 | /* Never override disk quota limits or use reserved space */ |
1448 | cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); | |
1449 | ||
655042cc | 1450 | sb->s_magic = OVERLAYFS_SUPER_MAGIC; |
420a62dd | 1451 | sb->s_xattr = ovl_xattr_handlers(ofs); |
ad204488 | 1452 | sb->s_fs_info = ofs; |
2bc5e5e8 | 1453 | #ifdef CONFIG_FS_POSIX_ACL |
7c4d37c2 | 1454 | sb->s_flags |= SB_POSIXACL; |
2bc5e5e8 | 1455 | #endif |
b836c4d2 | 1456 | sb->s_iflags |= SB_I_SKIP_SYNC; |
2bc5e5e8 CB |
1457 | /* |
1458 | * Ensure that umask handling is done by the filesystems used | |
1459 | * for the the upper layer instead of overlayfs as that would | |
1460 | * lead to unexpected results. | |
1461 | */ | |
1462 | sb->s_iflags |= SB_I_NOUMASK; | |
c00f94b3 | 1463 | sb->s_iflags |= SB_I_EVM_UNSUPPORTED; |
655042cc | 1464 | |
c6fe6254 | 1465 | err = -ENOMEM; |
b36a5780 | 1466 | root_dentry = ovl_get_root(sb, ctx->upper.dentry, oe); |
e9be9d5e | 1467 | if (!root_dentry) |
4155c10a | 1468 | goto out_free_oe; |
e9be9d5e | 1469 | |
e9be9d5e | 1470 | sb->s_root = root_dentry; |
e9be9d5e MS |
1471 | |
1472 | return 0; | |
1473 | ||
4155c10a | 1474 | out_free_oe: |
163db0da | 1475 | ovl_free_entry(oe); |
4155c10a | 1476 | out_err: |
ad204488 | 1477 | ovl_free_fs(ofs); |
1784fbc2 | 1478 | sb->s_fs_info = NULL; |
e9be9d5e MS |
1479 | return err; |
1480 | } | |
1481 | ||
f01d0889 | 1482 | struct file_system_type ovl_fs_type = { |
1784fbc2 CB |
1483 | .owner = THIS_MODULE, |
1484 | .name = "overlay", | |
1485 | .init_fs_context = ovl_init_fs_context, | |
1486 | .parameters = ovl_parameter_spec, | |
1487 | .fs_flags = FS_USERNS_MOUNT, | |
1488 | .kill_sb = kill_anon_super, | |
e9be9d5e | 1489 | }; |
ef94b186 | 1490 | MODULE_ALIAS_FS("overlay"); |
e9be9d5e | 1491 | |
13cf199d AG |
1492 | static void ovl_inode_init_once(void *foo) |
1493 | { | |
1494 | struct ovl_inode *oi = foo; | |
1495 | ||
1496 | inode_init_once(&oi->vfs_inode); | |
1497 | } | |
1498 | ||
e9be9d5e MS |
1499 | static int __init ovl_init(void) |
1500 | { | |
13cf199d AG |
1501 | int err; |
1502 | ||
1503 | ovl_inode_cachep = kmem_cache_create("ovl_inode", | |
1504 | sizeof(struct ovl_inode), 0, | |
1505 | (SLAB_RECLAIM_ACCOUNT| | |
f88c3fb8 | 1506 | SLAB_ACCOUNT), |
13cf199d AG |
1507 | ovl_inode_init_once); |
1508 | if (ovl_inode_cachep == NULL) | |
1509 | return -ENOMEM; | |
1510 | ||
a6293b3e AG |
1511 | err = register_filesystem(&ovl_fs_type); |
1512 | if (!err) | |
1513 | return 0; | |
2406a307 | 1514 | |
2406a307 | 1515 | kmem_cache_destroy(ovl_inode_cachep); |
13cf199d AG |
1516 | |
1517 | return err; | |
e9be9d5e MS |
1518 | } |
1519 | ||
1520 | static void __exit ovl_exit(void) | |
1521 | { | |
1522 | unregister_filesystem(&ovl_fs_type); | |
13cf199d AG |
1523 | |
1524 | /* | |
1525 | * Make sure all delayed rcu free inodes are flushed before we | |
1526 | * destroy cache. | |
1527 | */ | |
1528 | rcu_barrier(); | |
1529 | kmem_cache_destroy(ovl_inode_cachep); | |
e9be9d5e MS |
1530 | } |
1531 | ||
1532 | module_init(ovl_init); | |
1533 | module_exit(ovl_exit); |